Log Message:
-----------
Fix estimate_num_groups to be able to use expression-index statistics
when there is an expressional index matching a GROUP BY item.
Modified Files:
--------------
pgsql-server/src/backend/utils/adt:
selfuncs.c (r1.165 -> r1.166)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/utils/adt/selfuncs.c.diff?r1=1.165&r2=1.166)